Carton coating machine



H. B. E'GLEsToN ETAL 2,823,643

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Feb. 18, 1958 H. B. EGLESTON EIAL 2,

CARTON COATING MACHINE Filed March 25, 1955 18 Sheets-Sheet 18 M VWW) 11 Patented ,Feb. 18,1958

This invention :relates to an automatic conveyor ,systerm ,for loading, transferring, .and carry ng cartons and .has particular reierenceto amachine forwax-coating fiattop cartons ,such as-disclosed in application Serial No.

135,430 filed December 28, 1949 by Charles .H. Dixon,

now .Patent .-2,-730,288, :and :in Patent 2,663,981 issued -December129, 195 3 r to R. -S. Sanford.

Disposable cartonsmade of paperboard or other sheet material are well suited ;for the distribution of milk or otherfoods whencoated or impregnated to render them impervious. The coating,.usually applied as a hot liquid paraffin or wax-like substance, must be applied after the carton'has been creased and formed, and high production rates also require .rapid. cooling and hardening of the appliedmaterial. =The.coating must.be thorough,:inside and out, undamaged 1by' handling. .Strict sanitary standards as well as economic. requirements dictate'a minimum of handling, andv complete-automation is virtually a necessity. The generalaim of the inventiomis, therefore, to provide a fully automatic machine=forreceiving erected flat-top paper -cartons .of the typerdescribed, conveying them in timed sequence;and:.predetermined position, and discharging them. ;It.is1a more particular aim to provide iWiihSllCh'a machine azcomplete and effective inner .and outer :cooled moistureproofing coating 'fOI'iSllCh cartons at av high .rate of production.

-It is another object-to provide ,a'coating machine of the type .described which .is .easyto .clean andimaintain and fully :conformspto the rigoroussanitary requirements that must be.met;for dairy equipment andsimilar applications.

It,is.still another object to provide a high-speed .conveyor-sup plied coating machine a for simultaneously treating several cartons.

It is-a further object to economically and'efiiciently arrange 1b0th hot-coating and refrigerating stations for cartons conveyed through the-machine.

It is also an important object to provide an improved automatic conveyor system for such a machine.

It is {a further object to provide animproved automatic transfer system to convey hot-coated cartons from 'flap be temporarily sealed, so thatthe coated inner surface remains sanitary. It is, therefore, ,an additional object to provide a coatingrmachine for automatically closingv and sealing the cartonopening immediately after .applicationof the coating material to the cartonsjnner surface.

,Itis-a further object *in such ,a machine to provide means ,for simultaneously transferring a hot-coated container to a cooling system and closing and sealing the flap-through .whichthe innercoating was applied.

Briefly, in accordance with certain broader aspects of our invention, a coating machine is provided having a hot-dip coating tank and arefrigerated cooler through .which a continuous conveyor system is provided. The containers are fed to the machine on a conveyor and automatically loaded in groups on yacoating carrier, ;which.grasps the topsof the cartons and holds the top flaps open. The carrier conveys the cartons through the vhot liquid coating while maintaining a predetermined Eangular carton positionand without contacting the surfaces requiring coating. A transfer mechanism provides .for the transfer of each group of cartons to a cooling .carrier, which holds the cartons at the top and conveys .them--throughvthe..c,ooling unit, preferably including a water tray for cooling each carton base. A discharge mechanism unloads and discharges the completed containers. While the conveyor system'circuit is closed for continuous operation and is-arrangedfor use of a plurality of bothheating and cooling carriers, the heating .and cooling .carriersare confined to the heating and cooling units, respectively, for ,efficient operation.

.In accordance with .a particular further feature, the .transfer mechanismautomatically closes and temporarily .sc,als the filling'flapin' the course of transferring each hot-coated carton from the coating carrier to-the cooling carrier.

The objectsof the invention thus generally set forth, .together with other objects and ancillary advantages, are ,.attained by the construction and arrangement'shown by way of illustration in the accompanying drawings in .which:

Figure ,1 is a side view of a coating machine embodying the invention, showing the coater unit at the left andgthe cooler unit at the right;

Fig. 2 is a top view of-the;infeed mechanism includ- -.,ingthe carton tab breaker;

Fig. 3 is -a top view of the infeed:unit, partially in section, illustrating the infeed conveyor;

Fig. 4 is a side view of the infeed unit;

Fig. 5,is an end view of the infeed end of the coating machine in partial section to better illustrate the load- 2 mg unit;

Fig. 6 is a view taken along lines 66 of Fig. 5,.particularly illustrating the loading unit drive and actuating mechanism in cooperation with .the coating conveyor;

Fig. 7 is aperspective view illustrating the loading of a carton in a coating carrier;

Fig. 8 is a viewtaken along line 88 of Fig. 6 illustrating particularly the loading chute of the loader unit but with the contracting stop arrested;

Fig. 9 is a top view of the infeed end of the chute of the loading unit with the contracting stop in operation;

Figs. 10, 11, 12, 13 and 14 are semi-schematic views of the loading chute and loading rake of the loading unit showing successivesteps in transferring cartonsto the coating conveyor;

Fig. 15 is a perspective view of a carton portion show- .ing the filling fia-p turned back to the required position during coating;

Fig. 16 is a detail showing the triple-crank cam follower of the coating conveyor;

Fig. 17 is a side view of the cam follower of'Fig. 16;

Fig. 18 is an interior side view of. the coater unit showing the coating conveyor cams and the position of cartons atselected carriers along the conveyor;

Figs. 19 and 20 are semi-schematic details of the coating conveyor cams-and cam followers with the carton carrying angle indicated;

Fig. 21 is a semi-schematic side view illustrating the cooling transfer unit and flap-closing mechanism;

Fig. 22 is an end view of a portion of the transfer unit as viewed from the coater unit;

Fig. 23 is a view of the cooler unit from the discharge end and partially in section to better illustrate the cooling conveyor;

Fig. 24 is a side view of the discharge end portion of the cooling conveyor and the discharge unit particularly showing the conveyor cams;

Fig. 25 is a view of a portion of the cooler unit from the discharge end illustrating the discharge mechanism; and

Fig. 26 is a side view of the discharge mechanism.

While the invention is susceptible of various modifications and alternative constructions, there is shown in the drawings and will herein be described in detail the preferred embodiment; but it is to be understood that it is not thereby intended to limit the invention to the form disclosed, but it is intended to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as expressed in the appended claims.

General organization Referring now to the drawings, the coating machine 30 shown therein may be functionally described as having a coater unit 31 and a cooler unit 32. The coating unit, which contains a tank of heated wax, is the major lefthand structure of the machine as oriented in Fig. 1; and the cooling unit, which is refrigerated and also contains a water tank, is the major structure of the right-hand portion of Fig. -1. The invention, however, both in its components and in its combination of them, is better reflected by an analysis of the machine in terms of structural units and their particular functions and interaction with the other units of the machine. To this end, and to facilitate an understanding of the invention, the machine is described as an infeed unit 33, a coating loader 34, a hotcoating conveyor 35, a cooling transfer unit 36, a cooling conveyor 37, and a discharge unit 38. These units successively act upon the cartons supplied to them to perform the coating and cooling functions.

The machine is suitably mounted on a sturdy table or base structure 39 with cabinet enclosures for the heated coating and refrigerated cooling zones. A timed drive system 40 actuates the overall conveyor system, a main drive electric motor being suitably mounted on the coating cabinet enclosures.

In the particular embodiment described, the cooling transfer unit 36 also functions to close and seal the filling flap of each carton so that each carton may be stored or shipped in a sanitary condition for subsequent use.

An example of the type of carton employed is displayed in Fig. 15, this carton 41 being commonly employed for milk and known in the trade as a flat-top paper carton. One of its distinguishing characteristics, at least so far as the present invention is concerned, includes a fiat-top closure 42 with the upper portions 43 of a pair of opposite sides bent inwardly and folded just under the flat top of the carton so that the carton top has at least one pair of overhanging marginal ledge portions 44.

A filling flap 45 on the top of the carton is bendable upward as shown in the drawing, and is provided with a glue-coated area so that it can be finally sealed permanently in place after the carton is ultimately filled through the top opening under the sealing flap. This opening also provides access for the coating material, usually parafiin, to the inside of the container during the coating process. A tab 46 is pulled by the ultimate consumer to open a pouring aperture in the carton.

For reference in following the detailed description, the filling opening may be considered as at the back or rear portion of the fiat top 42, and the pair of top overhanging portions 44, significant withrespect to the coating placed in an upright position.

machine operation, may be defined as the top sides of the carton. The tab 46 is by this nomenclature at the front of the carton.

The formed cartons are supplied from a suitable source, such as forming or erecting machines of the type described and claimed in co-pending applications Serial No. 318,882, filed November 5, 1952 of James F. Earp. now Patent 2,770,175, and Serial No. 319,684, filed November 10, 1952 of Charles Z. Monroe and James F. Earp, now Patent 2,745,323, both of which applications are assigned to the assignee of the present invention. These both represent machines having a high production rate, and with which a coating machine of the type herein described is economically employable;

The structure of the carton described, with its converging upper side walls 43, provides a reinforced upper sealing surface against which the top closure can be pressed with suitable force to complete the carton enclosure when the carton is filled. As brought out in the following detailed description, the same overhanging margins 'or ledges of the container are utilized to safely and securely grasp and convey each container and transfer it through the operational steps of the coating machine. It will also become apparent that the conveying and transferring means are simple and direct, without damaging the carton or its coating and without preventing complete coating and cooling of all of the carton portions which must be rendered impervious to the ultimate carton contents.

Carton infeed unit At the infeed end of the coating machine the infeed unit 33 is mounted to receive cartons to be coated from a conveyor 50 and to release them one by one to a timed gate 51 of a rotary carrier 52. The carrier transfers the cartons with a positive feed to the infeed chute of the coating transfer or loading unit 34. A tab breaker 53, as an auxiliary apparatus operated by the infeed unit rotary carrier, tucks in each carton tab 46 to assure its final position prior to coating.

The infeed conveyor itself suitably comprises a moving metal plates, upon which the cartons 41 to be coated are I Guide rails 55 and 56 constitute what may be termed the front and back rails, respectively. The conveyor leads to a stationary plate or platform 57, positioned at the entrance to the rotary carrier'52. The conveyor itself may be suitably driven by any separate conveyor drive motor and need not be synchronized with the conveyor drive 40 of the coating machine. p

The conveyor loading requirements are simple, the cartons being simply placed upright on the conveyor with their front tab sides forward. This assures, without further adjustment or sorting, that the carton will be in the proper position for further automatic operations. The spacing between the cartons placed on the conveyor belt is not critical. The cartons will align themselves in a closely filed array behind the front carton on the platform 57, since the'front carton is restrained from advancing until the cumulative thrust of-the cartons on the moving conveyor behind it is suflicient to provide quick and sure loading. 7

The rotary carrier to which the top cartons are conveyed consists essentially (see Fig. 4) of a hub or collar 58 keyed to the vertical rotary shaft 59 of the infeed unit and having a plurality of radially extending pusher fins or paddles 60. 7 In the particular embodiment illustrated the paddle wheelso formed has four sections, and thus four paddles equally spaced and each defining a carton carrying position in front of each paddle. Each paddle also includes an inner flange or stop 61 defining the minimum radial spacing of the carton-from the paddle wheel axis and extending in the direction of rotation. Since the paddle wheel direction is in this case counterclockwise as viewed from the top (Figs. 2 and 3), arcuate bottom 

